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|Geography and history|
|It is the world's largest inland body of water. It has a surface area of 371,000 km² (143,000 sq. mi.), and a maximum depth of about 1025 m (3363 ft). Thus it has characteristics common to both seas and lakes. It is often listed as the world's largest lake, though it is not a freshwater one. It has a salinity of approximately 1.2%, about a third the salinity of sea water. The Caspian Sea is bordered by Russia (Dagestan, Kalmykia, Astrakhan Oblast), Azerbaijan, Iran (Guilan, Mazandaran and Golestan provinces), Turkmenistan (Balkan Province), and Kazakhstan, with the central Asian steppes to the north and east. On its eastern Turkmen shore is a large embayment, the Garabogazköl. The sea is connected to the Sea of Azov by the Manych Canal and the Volga-Don Canal. |
The sea is estimated to be about 30 million years old. It became landlocked about 5.5 million years ago. Discoveries in the Huto cave near the town of Behshahr, Mazandaran, (Southern land of Caspian Sea) suggest human habitation of the area as early as 75,000 years ago.
In classical antiquity it was called the Hyrcanian Ocean. It has also been known as the Khazar Sea. In Persian antiquity, as well as in modern Iran, it is known as the Mazandaran Sea. Old Russian sources call it the Khvalyn (Khvalynian) Sea after the Khvalis, inhabitants of Khwarezmia. Ancient Arabic sources refer to Bahr-e-Qazvin – the Qazvin Sea. The word Caspian is derived from "Kaspi", ancient peoples that lived to west of the sea in Transcaucasia.
|Photo title: Caspian Sea viewed from orbit|
|Photo credit: Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC|
|Marine life The Caspian holds great numbers of sturgeon, which yield eggs that are processed into caviar. In recent years overfishing has threatened the sturgeon population to the point that environmentalists advocate banning sturgeon fishing completely until the population recovers. However, prices for sturgeon caviar are so high that fisherman can afford to pay equally high bribes to authorities to look the other way, making regulations in many locations ineffective. Caviar harvesting further endangers the fish stocks, since it targets reproductive females. |
The Caspian Seal (Phoca caspica, Pusa caspica in some sources) is endemic to the Caspian Sea, one of very few seal species living in inland waters (see also Baikal Seal).
Oil The area is rich in energy wealth. As well as recently discovered oil fields, large natural gas supplies are also in evidence, though further exploration is needed to define their full potential. Geopolitical jockeying is taking place amongst Caspian-bordering countries, especially in the light of Middle East instability and the subsequent recasting of many Western countries' energy policies. Another factor influencing this is the new US military deployment to the Central Asian region. A key problem is the status of the Caspian Sea and the establishment of the water boundaries among the five littoral countries. Russia, Azerbaijan and Kazakhstan signed an agreement in 2003 to divide the northern 64% of the sea among themselves, although the other two bordering countries, Iran and Turkmenistan, did not agree to this. This is likely to result in the three agreeing nations proceeding with oil development regardless; Iranian and Turkmen development is likely to stall. At present, Azerbaijan and Kazakhstan have seen the biggest increase in oil production, an increase of 70% since 1992. Despite this, the region is still achieving less than potential output, with total regional production 1.6 million barrels (250,000 m³) per day, roughly equal to Brazil's production. This is expected to triple by 2010.
|Photo title: Beluga huso huso> sturgeon, an endangered species reknowned for its roe to produce caviar|
|Photo credit: FAO/FIGIS|
|The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, though it is not a freshwater lake.|
The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it is endorheic, i.e. there is no natural outflow (other than by evaporation) except the Manych Canal. Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans. The Caspian became landlocked about 5.5 million years ago. The level of the Caspian has fallen and risen, often rapidly, many times over the centuries. Some Russian historians claim that a medieval rising of the Caspian caused the coastal towns of Khazaria, such as Atil, to flood. In 2004, the water level was 28 metres/92 feet below sea level.
Over the centuries, Caspian Sea levels have changed in synchronicity with the estimated discharge of the Volga, which in turn depends on rainfall levels in its vast catchment basin. Precipitation is related to variations in the amount of North Atlantic depressions that reach the interior, and they in turn are affected by cycles of the North Atlantic Oscillation. Thus levels in the Caspian sea relate to atmospheric conditions in the North Atlantic thousands of miles to the north and west. These factors make the Caspian Sea a valuable place to study the causes and effects of global climate change.
The last short-term sea-level cycle started with a sea-level fall of 3 m from 1929 to 1977, followed by a rise of 3 m from 1977 until 1995. Since then smaller oscillations have taken place. These changes have caused major environmental problems.
based on information published in Wikipedia
printed on 2013/05/23 23:38:01